Refrigeration defrost system



Oct. 26, 1965 H, A, HALLs 3,213,637

REFRIGERATION DEFROST SYSTEM Filed Oct. 28, 1963 2 Sheets-Sheet 1 INVENTOR. Pf6-f A14/@94,0 A. MM5

BY Mx Oct. 26, 1965 H. A. HALLs 3,213,637

REFRIGERATION DEFRosT SYSTEM Filed Oct. 28, 1963 2 Sheets-Sheet 2 WCC Ibi Raaf/VH? caMPfssa/Q e 1N VENTOR. Eef-l 2, #www A. ,4m 5

United States Patent O 3,213,637 REFRIGERATIUN DEFROST SYSTEM Harold A. Halls, San Gabriel, Calif., assigner to Recold Corporation, Los Angeles, Calif., a corporation of California Filed Oct. 28, 1963, Ser. No. 319,097 9 Claims. (Cl. 62--278) This invention relates to an improvement in refrigeration defrost systems and in particular those systems utilizing hot gas defrosting, by eliminating the need for a separate hot gas line between the compressor and the evaporator, thus making it possible to operate with only the normal suction line and liquid line.

An object of the present invention is to eliminate the separate hot gas line between the Icompressor and the evaporator in refrigeration systems using a refrigerant ow control apparatus and hot gaseous refrigerant for defrosting purposes.

A still further object of the present invention is to provide a simple and inexpensive arrangement for the conversion of existing systems using other types of defrost, such as electric or water, to refrigeration systems utilizing hot gas defrosting and a refrigerant liow control apparatus.

Another principal object of the present invention is the elimination of the hot gas line utilized in hot gas defrost systems, by the addition of check valves and control valves, to reverse the direction of fiow of refrigerant gas through said system during defrosting.

Another .object of this invention is to provide a refrigeration system wherein the principles of hot .gas defrost operation as set forth in the patent to Lester K. Quick, No. 2,953,906 granted Sept. 27, 1960, are combined with the system of reversing the flow of refrigerant by the use of ow direction control means which may be manually or automatically operated to effect a simplification of the said defrost system and to insure safe operation thereof, particularly with respect to the operation .of the compressor during the defrosting operation.

A further object of the present invention is to provide a simple and inexpensive defrosting arrangement which may be integrated with the conventional refrigerating systems.

These and other objects and advantages of the invention will become apparent from the following detailed description .taken in connection with the accompanying drawings, in which:

FIGURE l is a diagrammatic view of a refrigeration system employing the apparatus of the present invention.

FIGURE 2 is a schematic representation illustrating an alternative form of the present invention.

In the specification, where I refer to reverse flow or to means to reverse the flow of refrigerant, it is understood that I am referring to a reversal of the refrigerant ow in at least a portion of the refrigeration system.

In the preferred embodiment of .the invention, FIG- URE 1 illustrates a refrigeration system in which the factors embodying the invention have been diagrammatically incorporated, and in which during the refrigeration cycle, discharge gas from compressor 1 passes through the high pressure line 2 into condenser 3 where it is condensed into a liquid and passes to receiver 4. Liquid refrigerant leaves the receiver through receiver outlet line 5, passes through the solenoid valve 6, through high pressure line 7 to the expansion valve 8 and then to the evaporator 9. Refrigerant vapor or gas leaves the evaporator through an evaporator outlet line 10, passes through the refrigerant flow control apparatus 11 to opening 12 of its outlet connection, through low pressure line segment 13 and check valve 14 which permits the refrigerant to flow to the compressor suction or low pressure line 3,2l3,637 Patented Oct. 26, 1965 lCe 15, solenoid valve 16, and return to the low pressure side of the compressor 1.

During the defrost cycle, gaseous refrigerant from the compressor 1 passes into high pressure line segment 17, and the valve 18 is now so positioned as to allow the gaseous refrigerant to pass into low pressure line 15 and into defrost line 19 due to the closed position of the check valve 14, to the coil on the drain pan 20. The gaseous refrigerant then fiows through evaporator inlet 21 to the evaporator 9 in which the gaseous refrigerant gives up heat to effect the defrosting and is at least partly condensed. Liquid and gaseous refrigerant then pass out of the evaporator through evaporator outlet line 10 to the refrigerant flow control apparatus 11 where gaseous refrigerant is separated from the liquid refrigerant. Gaseous refrigerant then passes through opening 12 of the outlet of the refrigerant flow control apparatus, while the liquid refrigerant is metered by a metering tube or orifice 22. A mixture of liquid and gaseous refrigerant passes through a portion of line 13, through line 23, check valve 24, line 25 and a portion of line 7; then through line 26, valve 27 and line 28 to inlet of compressor 1. During this fiow valves 6 and 16 are closed.

FIGURE 2 illustrates a method whereby the operation is controlled by three-Way valves, and in which during the refrigeration cycle, valve 30 is so positioned that the discharge gas from compressor 1 .passes into high pressure line 2 to condenser 3 where it is condensed into a liquid and passes as such into receiver 4. Liquid refrigerant leaves the receiver through receiver outlet line 5, through the second three-way valve 32, through high pressure line 7 to the expansion valve 8 and then into the evaporator 9. Refrigerant vapor leaves the evaporator through evaporator outlet line 10, .passes into the refrigerant flow control apparatus 11 to the opening of the outlet connection 12, through low pressure line segment 13 and through check valve 14 into low pressure line 15 through the first three-Way valve 30` into return line 31, and thus is returned to the low pressure side of the compressor 1.

During the defrost cycle, gaseous refrigerant from the compressor 1 passes into high pressure line segment 17, and the three-way valve 30 is now so positioned as to allow the gaseous refrigerant to pass into low pressure line 15 and into the defrost line 19 due to the closed position of the check valve 14, to the coil on the drain pan 20. The gaseous refrigerant then flows through evaporator inlet line 21 to the evaporator 9. Liquid and gaseous refrigerant then pass out of the evaporator through evaporator outlet line 10 to the refrigerant liow control apparatus 11 where gaseous refrigerant is separated from the liquid refrigerant. Gaseous refrigerant then passes through opening 12 of the outlet of the refrigerant flow control apparatus, while the liquid refrigerant is metered by a metering tube or orifice 22. A mixture Aof liquid and gaseous refrigerant passes through the check valve 24 by way of the outlet line 23 through high pressure line 2S, then through the second three-way valve 32, into by-pass line 28,-where it is returned to the inlet of the compressor 1. Y

While the preferred embodiments of the invention have been illustrated and described herein, the invention is not to be construed as limited to the specific details as disclosed herein, except as included in the following appended claims.

I claim:

1. In a refrigeration system of the character described, said system lincluding a high pressure system comprising a compressor, a high pressure line, a condenser, a receiver, a receiver outlet line, an expansion valve, a low pressure system comprising an evaporator, a low pressure line, a refrigerant ow control means and a low pressure line returning to said compressor, in combination with said refrigeration system; means for reversing the ow of refrigerant in said system during the defrost cycle comprising a series of control valves interposed in said high and llow pressure lines, check valve means for controlling the direction of the passage of liquid or gaseous refrigerant in said refrigeration system, said valves operating during the defrost cycle -to pass gaseous refrigerant to said evaporator, a ow control means normally positioned in the low pressure side of the system and operable during defrosting to separate liquid from gaseous refrigerant and to return the liquid refrigerant into the gaseous refrigerant at a controlled rate, and a by-pass system opere able during defrost for conducting the sa-id refrigerant to the compressor through a portion of the high pressure line bypassing the condenser and receiver and for conducting the said refrigerant to the intake of the compressor.

2. In a refrigeration system of the character described, sai-d system including a high pressure system comprising a compressor, a high pressure line, a condenser, a receiver outlet line, an expansion valve and a low pressure system comprising an evaporator, an evaporator outline line, a refrigerant flow control means, and a low pressure -line returning to said compressor, in combination with said refrigeration system; a valve interposed in said high pressure line and a valve interposed in said low pressure line, said valves operating to reverse the ow of gaseous refrigerant through said systems, thereby causing hot gaseous refrigerant to flow to the evaporator and remove frost therefrom, a series of check valves comprising means whereby said gaseous refrigerant is fed to the evaporator, a second valve in said high pressure line and connecting a ow line to the compressor suction and Ia second valve in said low pressure line to direct gaseous refrigerant to said compressor.

3. In a refrigeration system of the character described, including a high pressure system comprising a compressor, la high pressure line, a condenser, a receiver, a receiver outlet line, an expansion valve and a low pressure system comprising `an evaporator, an evaporator outlet line, a refrigerant flow control means and a low pressure line returning to said compressor, in combination with said refrigeration system; means for reversing the ow of refrigerant in said system during the defrost cycle, comprising a three-way control valve in said high pressure line, a second three-way control Valve in said low pressure line, said valves operating during the defrost cycle to pass hot gaseous refrigerant from said compressor to the evaporator coils to remove frost therefrom, said refrigerant ow control means separating liquid and 4gaseous refrigerant and returning said liquid and .gaseous refrigerant in controlled quantities to said system, check valves operating to return said refrigerant to the high pressure line, said three-way control valve interposed therein operating to direct refrigerant flow to the compressor suction inlet.

4. In a refrigeration system of the 'character described, including a high pressure system comprising a compressor, a high lpressure line, a condenser, a receiver, la receiver outlet line, an expansion valve, a low pressure system, comprising, an evaporator, an evaporator outlet line, a refrigerant flow control means and a low pressure line returning to said compressor, in combination with said refrigeration system; means for reversing the ow of refrigerant in said system during the defrost cycle, cornprising a valve means in said high pressure line, a second valve means in said low pressure line, said valve means operating during the defrost cycle to pass hot gaseous refrigerant from said compressor into the low pressure line through the evaporator coils, a flow control means separating liquid and gaseous refrigerant and returning said liquid and gaseous refrigerant in controlled quantities to Said System. a Series @f check valves operating to return said refrigerant to the high pressure line, and the said valve means in the high pressure line operating to direct said refrigerant to the compressor suction inlet.

5. In a refrigeration system wherein hot gas is employed to defrost the evaporator, the combination of means for reversing the flow of refrigerant during the defrosting operation and means operable during the defrosting to separate the liquid from the gaseous defrosting medium after defrosting and returning Ithe liquid into the gaseous defrosting medium at a controlled rate prior to its return to the compressor.

6. In a refrigeration system wherein hot gas is employed to defrost the evaporator, the combination of means for reversing the ow of refrigerant to deliver hot gas to the evaporator during defrosting through the normal low pressure line and means in the normal low pressure side of ythe system operating during defrost lto separate the liquid refrigerant from the gaseous refrigerant then leaving the evaporator and including means for returning the liquid into the gaseous refrigerant at a controlled rate prior to the return of the refrigerant medium to the compressor.

7. In a refrigeration system of the character described comprising a compressor, a refrigeration cycle high pressure line, a condenser, a receiver, a receiver outlet line, an expansion valve and a low pressure system comprising an evaporator, an evaporator outlet line, a refrigerant flow control means, and a refrigeration cycle low pressure line returning -to said compressor, means for reversing the flow to the evaporator for defrosting, comprising: a valve controlled bypass l-ine interposed in the low pressure line so positioned as to allow hot compressed gas from the cornpressor to ow into said low pressure line, a check valve in said low pressure line positioned to prevent hot gaseous refrigerant from reaching the refrigerant ow control means, and a bypass line permitting said hot gas to flow into Isa-id evaporator, then into said flow control means, a second check valve controlled bypass -line connecting the low pressure `and high pressure line and positioned to allow refrigerant to leave the refrigerant ow control means nad flow into the high pressure line, a valve in the high pressure line so positioned as to cause the refrigerant to bypass the receiver and condenser and return to the intake side of said compressor.

8. In a refrigeration system of the character described comprising a compressor, a refrigeration cycle high pressure line, a condenser, a receiver, a receiver outline line, an expansion valve and a low pressure system comprising an evaporator, an evaporator outline line, -a refrigerant flow control means, and a refrigeration cycle low pressure line retu-rning to said compressor, means for reversing the flow to the evaporator for defrosting, comprising: a three-way valve controlled bypass interposed in the low pressure line so positioned as to allow hot cornpressed gas from the compressor to flow into the low pressure line, a check valve in said low pressure line positioned to prevent hot gaseous refrigerant from reaching the refrigerant flow control means, and causing said hot gas to -llow through a bypass line connecting the low pressure line and the evaporator to remove frost therefrom, then into said flow control means, a second check valve controlled bypass line between the high pressure line and refrigerant flow control means, a three-way valve in the high pressure line so positioned as to cause the refrigerant to bypass the receiver and condenser and return to the intake side of said compressor.

9. In a refrigeration system of the character described comprising a compressor, a normal refrigeration high pressure line, a condenser, a receiver, a receiver outlet line, an expansion valve and a low pressure system comprising an evaporator, an evaporator outlet line, a refrigerant flow control means, and a normal refrigeration low pressure line returning to said compressor, means for reversing the flow of refrigerant to the evaporator for defrosting, comprising: a valve controlled bypass line interf refrigerant from reaching the refrigerant flow control means, and a bypass line permitting said hot gas to flow into said evaporator, then into said flow control means, a second check valve controlled bypass line positioned between the ow control means and the said high pressure line to allow refrigerant to leave the refrigerant flow control means, and valve controlled means connected in the high pressure line and so positioned as to cause the refrigerant to bypass the receiver and condenser and return to the intake side of said compressor.

References Cited bythe Examiner UNITED STATES PATENTS 2,729,950 1/ 60 Toothman 62-277 2,892,320 6/ 59 Quick 62-278 2,923,13 6 2/ 60 Tiede 62-278 2,953,906 9/ 60 Quick 62-278 3,012,414 12/61 La Porte 62-278 3,015,939 1/62 Brainard 62-278 3,077,086 2/ 63 Japhet 62-3 24 WILLIAM I. WYE, Primary Examiner. 

1. IN A REFRIGERATION SYSTEM OF THE CHARACTER DESCRIBED, SAID SYSTEM INCLUDING A HIGH PRESSURE SYSTEM COMPRISING A COMPRESSOR, A HIGH PRESSURE LINE, A CONDENSER, A RECEIVER, A RECEIVER OUTLET LINE, AN EXPANSION VALVE, A LOW PRESSURE SYSTEM COMPRISING AN EVAPORATOR, A LOW PRESSURE LINE, A REFRIGERANT FLOW CONTROL MEANS AND A LOW PRESSURE LINE RETURNING TO SAID COMPRESSOR, IN COMBINATION WITH SAID REFRIGERATION SYSTEM; MEANS FOR REVERSING THE FLOW OF REFRIGERANT IN SAID SYSTEM DURING THE DEFROST CYCLE COMPRISING A SERIES OF CONTROL VALVES INTERPOSED IN SAID HIGH AND LOW PRESSURE LINES, CHECK VALVE MEANS FOR CONTROLLING THE DIRECTION OF THE PASSAGE OF LIQUID OR GASEOUS REFRIGERANT IN SAID REFRIFERATION SYSTEM, SAID VALVES OPERATING DURING THE DEFROST CYCLE TO PASS GASEOUS REFRIGERANT TO SAID EVAPORATOR, A FLOW CONTROL MEANS NORMALLY POSITIONED IN THE LOW PRESSURE SIDE OF THE SYSTEM AND OPERABLE DURING DEFROSTING TO SEPARATE LIQUID FROM GASEOUS REFRIGERANT 